Selective chloridization of metals



SELECTIVE CHLORIDIZATION OF METALS Filed Dec. 20, 1950 E INVENTOR BY +/Q$4 ATTORNEYS mama Ma 9, 1933 UNITED STATES PATENT OFFICE ING AND DEFINING COMPANY, 01 Y JERSEY sELncrrvn cnnonrmznrron or KELALS Application filed December 20, 1930. Serial No. 508,702.

' This invention relates to a process forrefining metals, and more particularly to a process for separating meals by selective chloridization.

- The invention is applicable to the separation of various metals which can be selectively ehloridized and provides for introducing chlorine into a bath of molten metals under such conditions that an efficient separation may be obtained.

This application is a continuationin part of my copending application Serial .No. 145,402, filedNovember 1, 1926, for Method of dezincing'lead, which issued as Patent No. 1,792,210 on February 10,1931.

In applying chlorine to certain metals for the formation of metal chlorides, it has been found that the process is impeded by the tendencyv of the metals to oxidize and by the difliculty of maintaining a fluid slag of the metal chlorides. The present invention provides for overcoming these difiiculties by causing the slag to remain fluid at the temperature of treatment and by introducing the chlorine under such conditions that oxidationof the metals is largely prevented. For this purpose a cover consisting of a chloride slag of comparatively low melting point is maintained on the surface of the bath and the chlorine is introduced into the bath under this slag. The slag forms a seal over the surface of the bath and prevents undesirable oxidation and also mixes with the ing the .chlorine under such conditions that corrosion of the apparatus is reduced to a minimum. A 4

' The invention is particularly useful in removing various metals such as zinc, aluminum, magnesium andalkali earth metals from lead or an alloy of lead and other metals, such as antimony, bismuth, etc. Likewise it may be applied to the separation of Y other metals, as'for example, lead from mixtures of bismuth and lead, or antimony and lead, or antimony, arsenic and lead; also for theseparation of alkali earth metals and/or magnesium from zinc or lead and zinc or lead nssnoAmx mar-Enron, or 01mm, nnnnasxa, ASSIGNOB 'ro martian sm'r- NEW YORK, N. Y., a conronagrron or new I from bismuth. In general the invention is useful for the separation of any metal which is more readily chloridized, from a metal which is less readily chloridized.

The invention also consists in certain new and original features of construction and combinations of parts hereinafter set forth and claimed.

Although the novel features which are believed tobe characteristic of this invention will be particularly pointed out in the claims appended hereto,.the invention itself,

as to its objects and advantages, and the man- 7 ner in which it may be carried out may be better understood by referring to the follow ing description taken in connection with the accompanylng drawing forming a part thereof, in which the figure is an elevation of a form of apparatus suitable for carrying out the process.

In the following description and in the claims parts will .be identified by specific names for convenience, but they are intended to be as generic in their application to similar parts as the art will permit.

Referring now to the drawing, the kettle 1 Y may be filled with molten metal containing a readily chloridizable impurity to the height indicated by the line 14. Supported by the top rim of the kettle is a unit comprising a motor 2 and pump 3, the motor being supported as by channel irons extending across the kettle and resting upon the rim thereof. The pump is suspended from the motor and is located preferably near the bottom of the kettle. The unit may be provided with a link 4 5 by means of which the unit may be carried iv v a about the plant.

Supported also on the rim of the kettle 1 is a reaction chamber 6, the bottom being closed and having a discharge pipe 7 connected 5 thereto which extends down beneath the surface of the bath a suitable distance. The reaction chamber 6 may be supported by two I-beams 8 extending across the kettle, the I- beams having secured at their lower flanges I transverse members 9 on which the reactlon cylinder rests. The top of the reaction chamber may be provided with a flange 10 to which may be secured ahead 11. A connecting pipe be the source of chlorine, which may be in the form of a chlorine tank 18 immersed in a vessel 19 filled with water and kept at an appropriate temperature. Suitable piping 20 may connect the chlorine tank with the reaction cylinder and a valve 21 may be provided for controlling the flow of the chlorine. In carrying out the above process the motor and pump and reaction chamber are.

placed in position on the kettle which has been filled with molten metal to the level indicated for example, by line 14. Appropriate connections may then be made between the various parts of the apparatus after which portions of the molten metal may be withdrawn from the bath by means of ump 3 and supplied to the reaction cham er and caused to flow downwardly therein. At the same time chlorine is introduced. from chlorine cylinder 18 and caused to react with the impurities in the molten metal.

The rate of passage of the molten metal through the reaction chamber and rate of.

application of the chlorine gas thereto may be controlled by suitable regulation of pump 3 and valve 21 respectively so that the chlorine is adsorbed by the metal due to the resultant reaction at a rate such as to produce a partial vacuum in the reaction chamber and cause the metal of the bath to rise an appreciable distance therein.

By operating the apparatus with a partial vacuum the chlorine does not attack the walls of the chamber to an appreciable extent, and the tendency of the chamber to corrode is reduced to a minimum. Furthermore, it is to be noted that the release from pressure of the chlorinefrom the high pressure of the original tank or bottle to the pressure of the reaction chamber will cause the same to undergo a drop in temperature which will tend to neutralize the heat of the reaction and prevent the temperature of the bath from rising'above the desired value. Furthermore,

the circulation offhe metal caused by the above described apparatus serves to agitate the bath below the surface thereof and assists in securing the desired reaction.

In applying the process specifically to the treatment of a lead bath to remove impurities therefrom as chlorides, the bath may be heated to a temperature adapted to efficiently carry on the reaction, preferably a temperature between the melting point of lead and 1000F., as for example, 670 F. to 750 F. It is desirable to avoid a temperature above these limits in order to reduce the corrosion of the containers by the chlorine gas.

A chloride slag of a readily fusible chloride. such as a zinc chloride, is then added or allowed to accumulate on the bath in sufficient quantities to completely cover and seal the same and prevent oxidation by contact with the atmospherel This slag may be formed from the bath and allowed to accumulate or may be added thereto depending upon.

the impurities which it is desired to remove;

In treating a lead bath for the removal of zinc, for example, by the introduction of chlorine, a zinc chloride slag will rapidly form and may be allowed to accumulate on the surface thereof and will be fusible at the above mentioned temperature range although a portion of the slag at the surface may solidify due to the heat radiation therefrom. The fluid portion however completely covers and seals the bath.

In treatinga lead bath for the removal of certain other metals, such as alkali earth metals, it is preferable to introduce a slag of zinc chloride from an external source inasmuch as the alkali earth "metal chloride would be infusible at the temperature range above mentioned and would form a so-called dry dross which would not spread over the bath nor form an effective seal. Furthermore,

the oxidation ofthe bath would produce litharge which would also be insoluble at the above temperatures and further impede the process.

In addition a secondary reaction occurs between the chlorides of the alkali earth metal, zinc and/or lead to form a chloride of the alkali earth metal which enters the sla throwing the lead or zinc back into the batfi.

After the surface of the bath has been covered by a molten slag either separately introduced or formed therein, as above described, chlorine is introduced by continuously withdrawing a portion of the bath and passing it through the reaction chamber wherein it is reacted with chlorine -to form chlorides which are carried by the stream back into the bath. The chlorides then rise to the surface and mix with the slag which is already present thereon.

The chloride slag which is produced may be removed from the bath in any suitable manner and treated for the recovery of the metal values therefrom.

The invention has been described for convenience as applied to certain metals but it. 4

is obvious that it is applicable to other combinations of metals which are selectively chloridizable and that the metals specifically mentioned are only illustrative. l

Although certain novel features of the invention have been shown and described and are pointed out in the annexed claims, it will said molten lead from a 'bath' and cient'to seal the i ll berm returning the reaction products therefrom ble, metallic chlori suficienttosealthebathfromeom tactwith theatm he, remo" batha'ndpasaingaameintoarea'ction a j 1. The process of a molten metal for the removal there of a more readily chloridizable metal w lqhrises continuousl removing a portiono said molten meta from a bath and said portion through a reaction chamber 'w ile admitting chlorine to said chamber at such a rate that a partial vacuum is continuously produced therein and then returning the products of reaction to the bath.

2. The process of treating molten lead for the removal therefrom of a more readily chloridizable metal which com rises continr uously removin a portion of sa d molten lead from a. bath an passing said portion through a reaction chamberwhile admitting chlorine to said chamber at such a rate that a partial vacuum is continuously produced therein and m then returning the products of reaction to the bath.

8. The process of treatin molten lead for the removal of'zinc there m'which comprises continuously removing a portion of gassing said rtion through a reaction 0 amber while admitting chlorine to said chamber at such a rate that a partial vacuum is continuously produced therein and then returning a the products of reaction to the bath.

4. In the selective chloridization of metals the improvement which comprises establishing a molten bath of such metals, covering the surface of said molten bath with a readily increased in quantity by the chloridi zing o eration as same progresses, continuou withdrawing portions of the molten bath an subjecting same to the action of chlorine in i m a closed reaction chamber and returnin the I reaction products thereof to the molten th 3*; a point substantially beneath the chloride 5 The process of purifying metal coualkaline earth group which comprises establishing a molten bath of said contaminated Leo-1,461,.

ber while admitting chlorine is said amtber at such a tate that partial vacuum is con-- tinuously producedtherein, and returning as reaction products from the reaction chamreturning the reaction products to the molten bath substantially below the surface thereof whereby the chloride of the more readily chloridizable metal rises to the surface of the bath and completely seals same from" contact 7 with the atmosphere.

In testimony whereof Lhave hereunto my hand. Y I I SSE OA'llMAN BETTEBTON 8 fusible metallic chloride slag which will be taminated with one or more metals of the I metal, applying a readily fusible metallic chloride cover to said bath in quantities sufibath from contact with the atmosphere, continuously removing a tion of said contaminated metal rem the bath and passing same into a reaction chamintimate contact with chlorine gas and d ii' i 'fyi man tam e recess 0 pun ng con by one or more other metals which establishing a molten batlrof said contaminated metal applying aread ly fuside cover to as bath in quantities "tion of said con 

